1. Field of the Invention
The present invention relates to a character display device for displaying characters for OSD (On-Screen Display), which are generally used for indicating the number of a channel currently being received, the current sound volume and so forth on a TV screen or the like, and, more particularly, to a character display device displaying a wallpaper character (background image or background character) on the whole screen as well as the characters for OSD, together with the character displaying method thereof. displaying method thereof.
2. Description of the Related Art
FIG. 5 is a schematic view showing a fundamental configuration of a conventional character display device. In the figure, reference numeral 1 denotes a vertical position register for storing the vertical displaying position of the characters for OSD (hereinafter refereed to just as xe2x80x9cOSD charactersxe2x80x9d), numeral 2 denotes a horizontal position register for storing the horizontal displaying position of the OSD characters, and numeral 3 denotes a display timing detection circuit which detects the timing for displaying each of the OSD characters through a counting operation of the horizontal synchronous signals H and the vertical synchronous signals V, and outputs a data indicating displaying position (or just xe2x80x9cdisplay-position dataxe2x80x9d hereinafter) for each of the OSD characters. Further, reference numeral 4 denotes a display control circuit which outputs a command signal to display (hereinafter refereed to just as a xe2x80x9cdisplay command signalxe2x80x9d), whenever the display timing detection circuit 3 outputs the display-position data.
Reference numeral 5 denotes a RAM which stores character codes for one or more OSD characters, and outputs the corresponding one of the stored character codes when it receives a display command signal from the display control circuit 4. Reference numeral 6 denotes a ROM, which, on receiving the character code from the RAM 5, outputs a character data specified by the thus received character code. Reference numeral 7 denotes a shift register which synchronizes with the display command signal sent from the display control circuit 4, and inputs and/or outputs the character data received from the ROM 6.
The operational movement of the above-described conventional character display device is as follows.
First, the display timing detection circuit 3 counts the number of horizontal synchronous signals HL and vertical synchronous signals V to obtain the current scanning position on the screen, in order to detect the timing for displaying the OSD characters.
Thereafter, the display timing detection circuit 3 compares the thus obtained current scanning position on the screen and the displaying position of each of the OSD characters, (which position is deduced from the stored value in the vertical position register 1 and that in the horizontal position register 2), and outputs the display-position data for each of the OSD characters when they coincide with each other.
When the display control circuit 4 receives the display-position data from display timing detection circuit 3, it outputs display command signals respectively to the RAM 5, the ROM 6 and to the shift register 7, in order to produce the OSD character corresponding to the display-position data.
Thereafter, when the RAM 5 receives the display command signal from the display control circuit 4, it outputs a character code corresponding to the display-position data to the ROM 6.
In this way, when the character code corresponding to the display-position data is outputted from the RAM 5, the ROM 6 outputs a character data specified by the character code, such as a letter data, picture data and so on, to the shift register 7.
Then, the shift register 7 inputs and/or outputs the character data, synchronizing with the display command signal outputted from the display control circuit 4, and when the character data is outputted from the shift register 7, an OSD character is sent out on the basis of the thus outputted character data.
Since the conventional character display device is configured as explained above, OSD characters can be displayed in any arbitrary position on a display screen. However, there has been no means provided for displaying a wallpaper on the whole display screen.
The present invention has been achieved in consideration of the aforementioned, and it is an object of the present invention to provide a character display device, which is capable not only of displaying an OSD character in any arbitrary position of the display device, but of displaying a wallpaper on the whole screen, together with a character displaying method.
In order to achieve the above object, the character display device according to the present invention comprises: control means for controlling timing for displaying OSD characters and wallpaper characters, through counting horizontal synchronous signals and vertical synchronous signals; storing means for storing character data for OSD characters and for wallpaper; and output means for outputting, upon receiving a command to display either one of the OSD characters or the wallpaper characters, the corresponding character data stored in the storing means.
In the above configuration, the output means combines the character data for OSD characters and character data for the wallpaper, when the timing for displaying OSD characters and wallpaper characters coincide with each other.
The character display device according to the present invention constructed as above is further provided with at least one of a first and second setting means; respectively, for setting the number of dots for a wallpaper character in the horizontal direction and in the vertical direction.
The character displaying method provided for accomplishing the above object comprises of: counting horizontal synchronous signals and vertical synchronous signals to control the timing for displaying OSD characters and wallpaper characters; and outputting, upon receiving a command to display either one of an OSD characters or a wallpaper character, a corresponding one of the OSD character and wallpaper stored in a storing means.
The above character displaying method further comprises combining the character data for OSD characters and character data for wallpaper characters, when the timing for displaying OSD characters and wallpaper characters coincide with each other.
The character displaying method according to the present invention further comprises preliminarily setting the number of dots for wallpaper character in at least one of the horizontal and vertical directions.
As explained above, according to the first aspect of the present invention, since the character display device is configured such that there is provided an output means which, when the control means outputs a character display command signal, outputs either the character data for an OSD character or that for a wallpaper character, both stored in the storing means, not only an OSD character can be displayed in any arbitrary position on the screen, but wallpaper can also be displayed on the whole screen.
According to the second aspect of the present invention, since the character display device is configured such that there is provided an output means which, when timing for displaying an OSD character and that for displaying a wallpaper character coincide with each other, combines the character data for the OSD character and that for the wallpaper character, so that both character data are displayed in a superimposed manner.
Further, according to the third aspect of the present invention, since the character display device is configured such that there is provided at least one of a first and second setting means; respectively, for setting the number of dots in the horizontal and vertical directions of the wallpaper character, the picture of the wallpaper can be finely adjusted.
Further according to the fourth aspect of the present invention, since the character displaying method is arranged such that when the timing for displaying either one of the OSD character or wallpaper character is detected, either the character data for an OSD character or that for a wallpaper character both stored in a memory is outputted, not only an OSD character can be displayed in any arbitrary position on the screen, but a wallpaper can also be displayed on the whole screen.
Still further, according to the fifth aspect of the present invention, since the character displaying method is arranged such that when the timing for displaying the OSD character and that for displaying a wallpaper character coincide with each other, the character data for the OSD character and that for the wallpaper character are combined, and both data can be displayed in a superimposed manner.
Yet still further, according to the sixth aspect of the present invention, since the character displaying method is arranged such that the number of dots for wallpaper characters are preliminarily set in at least one of the horizontal and vertical directions, the picture of the wallpaper can be finely adjusted.